Compression ridges was :Do you dry the ribs, along with the board, prior to gluing ?

[Prof. Euphonious Thump]

--- Greg Newell <gnewell at ameritech.net> wrote:

> Thump,
> 	You bring up a good point. Stiffness is desired in
> the high treble
> but what about the bass where flexibility seems to
> rule? The board would
> lose crown due to compression set and therefore
> bearing which is no doubt
> why some "rebuilders" drop the plate to achieve it.

Yes, but there's often too much bearing in the bass,
to begin with. It's pretty well accepted, these days
that there should be minimal bearing on the bass
bridge. So, with the "laminate recrowning" method, I'd
not do much, there. So you'd have a  little more
stiffness from the wood's aging ( which I don't
believe would be troublesome, as stiffness also means
better vibratory transmission throughout the board  )
and a  little less crown. Basses in old pianos, I
believe, sound just fine with bridge repairs and new
strings. ( Adequate remedy. )

> Or would that be to
> re-achieve it? It seems to me that it's better to
> achieve the stiffness you
> want as a product of design rather than a byproduct
> of age. 

    Yes, but I believe that the result of age should
be considered. Bust up an old piano, and you can feel
how stiff the old soundboard wood has become.      
    Almost "bamboo-like" !

    Do you feel that
> any compression set or at least that which results
> in compression ridges is
> an inadequate design which did not support or resist
> downbearing?

    That, and extreme humidity swings. I believe that
a CC board will be more susceptible to the compression
set that humidity swings cause, than an RC board. But
once "the damage has been done" it won't continue.
Which is another reason I'd like to see more old wood
re-used, than putting in new wood that has yet to
develop it's compression set. 
( But, again, with the well-designed new R&C boards
this is less of an issue. ) 
 
> Specifically in a CC designed board what could be
> done to design in more
> support or resistance? 

   I'm not advocating designing CC boards. RC boards
are better. But if you HAVE a  CC board with good
wood, I'm suggesting you could MAKE an "RC" board out
of it, by making the existing ribs laminated:  with
either flat strips glued to them in a flexed
condition, curved-cut ribs, or ribs that are glued on
humid ( Ron's suggestion via Ric ) or a  combination
of all of the above !
    This is "uncharted territory" and I confess that
I'm "throwing these ideas out", in hopes that other
techs will experiment with them, and get back to us
with their findings.  
     The "piano business" in Athens, Ga., is such that
I'm barely able to survive at it, and have scant
opportunity for such "experimenting".

     Peace,
     G


Oh.... didn't see this stuff:

 Certainly size, shape and
> placement/orientation of
> ribs, but is there something else? Since in a CC
> board the board itself
> takes much of the load should the board be thicker
> in order to
> resist/support better? That would seem to inhibit
> the bass movement
> dramatically. 

   One of the BEST sounding piano basses I EVER heard
was an old Packard upright with a board about 1/2 "
thick, and wide flat ribs ( by everyones' estimate, a
CC board ). But, then, it may have had heavy scaling,
etc..  I don't mention this to be a  nusance. I only
mention it to say that my experience has contradicted
some of the precepts put forth on this list, and I
want to know why ???? 


 I maintain, at least by my thinking,
> that the reuse of an old
> board in a CC arrangement is a detriment however
> much and not a feature. 

   Well, MAYBE, overall: unless you live where no-one
will pay for a  new RC board. There are other issues
with old boards that are negatives: like old glue
joints, etc.. But there may also be "plusses" that are
being ignored, and ways to make old boards "work". (
And "work" well ! )   That's all I'm saying. An area
that's not been explored adequately, IMHO. 


> could be less potentially problematic in a RC or
> RC&S board but I still
> don't see how it could be better. 
    "Better" is largely subjective.

> 	As an aside, wouldn't the age reactions that you
> wrote of earlier
> which cause the board to become more brittle,
> however much, lend towards
> easier and/or earlier cracks or ridges?  

Nope. The cracks and ridges have already happened. I'd
contend it would make it less susceptible. 

Thump


>


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